Fix some bugs and memory leaks in CBOT

* Added CBotStack::StackOver() calls where it was possible
  to go out-of-bounds when calling CBotStack::AddStack().
* Fixed some bugs in CBotExternalCallClass

src/CBot/CBotDefParam.cpp

@@ -137,6 +137,7 @@ bool CBotDefParam::Execute(CBotVar** ppVars, CBotStack* &pj)
     while ( p != nullptr )
     {
         pile = pile->AddStack();
+        if (pile->StackOver()) return pj->Return(pile);
         if (pile->GetState() == 1) // already done?
         {
             if (ppVars != nullptr && ppVars[i] != nullptr) ++i;

src/CBot/CBotExternalCall.cpp

@@ -82,19 +82,23 @@ int CBotExternalCallList::DoCall(CBotToken* token, CBotVar* thisVar, CBotVar** p
 
     CBotExternalCall* pt = m_list[token->GetString()].get();
 
-    if (pStack->IsCallFinished()) return true;
+    if (thisVar == nullptr && pStack->IsCallFinished()) return true;  // only for non-method external call
-    CBotStack* pile = pStack->AddStackExternalCall(pt);
 
-    // lists the parameters depending on the contents of the stack (pStackVar)
+    // if this is a method call we need to use AddStack()
-    CBotVar* pVar = MakeListVars(ppVar, true);
+    CBotStack* pile = (thisVar != nullptr) ? pStack->AddStack() : pStack->AddStackExternalCall(pt);
 
-    // creates a variable to the result
+    if (pile->GetState() == 0) // the first time?
-    CBotVar* pResult = rettype.Eq(CBotTypVoid) ? nullptr : CBotVar::Create("", rettype);
+    {
+        // lists the parameters depending on the contents of the stack
+        CBotVar* pVar = MakeListVars(ppVar, true);
+        pile->SetVar(pVar);
 
-    pile->SetVar(pVar);
+        CBotStack* pile2 = pile->AddStack();
-
+        // creates a variable to the result
-    CBotStack* pile2 = pile->AddStack();
+        CBotVar* pResult = rettype.Eq(CBotTypVoid) ? nullptr : CBotVar::Create("", rettype);
-    pile2->SetVar(pResult);
+        pile2->SetVar(pResult);
+        pile->IncState(); // increment state to mark this step done
+    }
 
     pile->SetError(CBotNoErr, token); // save token for the position in case of error
     return pt->Run(thisVar, pStack);
@@ -107,7 +111,8 @@ bool CBotExternalCallList::RestoreCall(CBotToken* token, CBotVar* thisVar, CBotV
 
     CBotExternalCall* pt = m_list[token->GetString()].get();
 
-    CBotStack* pile = pStack->RestoreStackEOX(pt);
+    // if this is a method call we need to use RestoreStack()
+    CBotStack* pile = (thisVar != nullptr) ? pStack->RestoreStack() : pStack->RestoreStackEOX(pt);
     if (pile == nullptr) return true;
 
     pile->RestoreStack();
@@ -163,8 +168,7 @@ bool CBotExternalCallDefault::Run(CBotVar* thisVar, CBotStack* pStack)
         return false;
     }
 
-    if (result != nullptr) pStack->SetCopyVar(result);
+    pStack->Return(pile2); // return 'result' and clear extra stack
-
     return true;
 }
 
@@ -187,8 +191,8 @@ CBotTypResult CBotExternalCallClass::Compile(CBotVar* thisVar, CBotVar* args, vo
 
 bool CBotExternalCallClass::Run(CBotVar* thisVar, CBotStack* pStack)
 {
-    if (pStack->IsCallFinished()) return true;
+    assert(thisVar != nullptr);
-    CBotStack* pile = pStack->AddStackExternalCall(this);
+    CBotStack* pile = pStack->AddStack();
     CBotVar* args = pile->GetVar();
 
     CBotStack* pile2 = pile->AddStack();
@@ -207,9 +211,8 @@ bool CBotExternalCallClass::Run(CBotVar* thisVar, CBotStack* pStack)
         return false;
     }
 
-    if (result != nullptr) pStack->SetCopyVar(result);
+    pStack->Return(pile2); // return 'result' and clear extra stack
-
     return true;
 }
 
-}
+} // namespace CBot

src/CBot/CBotInstr/CBotDefClass.cpp

@@ -360,6 +360,7 @@ bool CBotDefClass::Execute(CBotStack* &pj)
             if ( p != nullptr) while ( true )
             {
                 pile2 = pile2->AddStack();                      // place on the stack for the results
+                if (pile2->StackOver()) return pj->Return(pile2);
                 if ( pile2->GetState() == 0 )
                 {
                     if (!p->Execute(pile2)) return false;       // interrupted here?

src/CBot/CBotInstr/CBotFunction.cpp

@@ -445,7 +445,7 @@ bool CBotFunction::Execute(CBotVar** ppVars, CBotStack* &pj, CBotVar* pInstance)
         pile->IncState();
     }
 
-    if ( !m_block->Execute(pile) )
+    if (!pile->GetRetVar(m_block->Execute(pile)))
     {
         if ( pile->GetError() < 0 )
             pile->SetError( CBotNoErr );

src/CBot/CBotInstr/CBotInstrCall.cpp

@@ -138,6 +138,7 @@ bool CBotInstrCall::Execute(CBotStack* &pj)
     if ( p != nullptr) while ( true )
     {
         pile = pile->AddStack();                        // place on the stack for the results
+        if (pile->StackOver()) return pj->Return(pile);
         if ( pile->GetState() == 0 )
         {
             if (!p->Execute(pile)) return false;        // interrupted here?

src/CBot/CBotInstr/CBotInstrMethode.cpp

@@ -164,6 +164,7 @@ bool CBotInstrMethode::ExecuteVar(CBotVar* &pVar, CBotStack* &pj, CBotToken* pre
         }
         ppVars[i++] = pile2->GetVar();              // construct the list of pointers
         pile2 = pile2->AddStack();                  // space on the stack for the result
+        if (pile2->StackOver()) return pj->Return(pile2);
         p = p->GetNext();
         if ( p == nullptr) break;
     }

src/CBot/CBotInstr/CBotNew.cpp

@@ -189,6 +189,7 @@ bool CBotNew::Execute(CBotStack* &pj)
         if (p != nullptr) while ( true)
         {
             pile2 = pile2->AddStack();  // space on the stack for the result
+            if (pile2->StackOver()) return pj->Return(pile2);
             if (pile2->GetState() == 0)
             {
                 if (!p->Execute(pile2)) return false;   // interrupted here?

src/CBot/CBotInstr/CBotTwoOpExpr.cpp

@@ -357,6 +357,7 @@ bool CBotTwoOpExpr::Execute(CBotStack* &pStack)
 
     CBotStack* pStk2 = pStk1->AddStack();               // adds an item to the stack
                                                         // or return in case of recovery
+    if (pStk2->StackOver()) return pStack->Return(pStk2);
 
     // 2nd state, evalute right operand
     if ( pStk2->GetState() == 0 )
@@ -514,7 +515,6 @@ bool CBotTwoOpExpr::Execute(CBotStack* &pStack)
     pStk2->SetVar(result);                      // puts the result on the stack
     if ( err ) pStk2->SetError(err, &m_token);  // and the possible error (division by zero)
 
-//  pStk1->Return(pStk2);                       // releases the stack
     return pStack->Return(pStk2);               // transmits the result
 }
 

src/CBot/CBotProgram.cpp

@@ -34,7 +34,7 @@
 namespace CBot
 {
 
-CBotExternalCallList* CBotProgram::m_externalCalls = new CBotExternalCallList();
+std::unique_ptr<CBotExternalCallList> CBotProgram::m_externalCalls;
 
 CBotProgram::CBotProgram()
 {
@@ -395,6 +395,8 @@ int CBotProgram::GetVersion()
 
 void CBotProgram::Init()
 {
+    m_externalCalls.reset(new CBotExternalCallList);
+
     CBotProgram::DefineNum("CBotErrZeroDiv",    CBotErrZeroDiv);     // division by zero
     CBotProgram::DefineNum("CBotErrNotInit",    CBotErrNotInit);     // uninitialized variable
     CBotProgram::DefineNum("CBotErrBadThrow",   CBotErrBadThrow);    // throw a negative value
@@ -420,9 +422,10 @@ void CBotProgram::Free()
     CBotToken::ClearDefineNum();
     m_externalCalls->Clear();
     CBotClass::ClearPublic();
+    m_externalCalls.reset();
 }
 
-CBotExternalCallList* CBotProgram::GetExternalCalls()
+const std::unique_ptr<CBotExternalCallList>& CBotProgram::GetExternalCalls()
 {
     return m_externalCalls;
 }

src/CBot/CBotProgram.h

@@ -19,11 +19,12 @@
 
 #pragma once
 
-#include "CBot/CBotTypResult.h"
 #include "CBot/CBotEnums.h"
 
-#include <vector>
 #include <list>
+#include <memory>
+#include <string>
+#include <vector>
 
 namespace CBot
 {
@@ -31,6 +32,7 @@ namespace CBot
 class CBotFunction;
 class CBotClass;
 class CBotStack;
+class CBotTypResult;
 class CBotVar;
 class CBotExternalCallList;
 
@@ -335,11 +337,11 @@ public:
     /**
      * \brief Returns static list of all registered external calls
      */
-    static CBotExternalCallList* GetExternalCalls();
+    static const std::unique_ptr<CBotExternalCallList>& GetExternalCalls();
 
 private:
     //! All external calls
-    static CBotExternalCallList* m_externalCalls;
+    static std::unique_ptr<CBotExternalCallList> m_externalCalls;
     //! All user-defined functions
     std::list<CBotFunction*> m_functions{};
     //! The entry point function